With the increase in different types of devices communicating over networks to servers and other computing devices, usage of 3GPP LTE systems has increased. In particular, both typical user equipment (UE) such as cell phones and Machine Type Communications (MTC) UEs currently use 3GPP LTE system. MTC UEs pose a particular challenge as they are less computationally powerful and have less power for communication. Moreover, many MTC UEs are configured to remain essentially indefinitely in a single location. Examples of such MTC UEs include smart meters or sensors (e.g., sensing environmental conditions) or microcontrollers in appliances or vending machines.
Unfortunately, in a number of cases, MTC UEs do not have sufficient power for communications with the nearest serving base station (enhanced Node B (eNB)). Similar problems arise for non-stationary wireless UEs, such as mobile phones, that are disposed in a network area with poor coverage, i.e., one in which the link budget is several dB below typical network values. Transmission power may not be able to be increased either by a UE or eNB in situations in which UEs are in such areas. To achieve a particular coverage extension target and obtain additional dB in link budget, signals may be repeatedly transmitted to or from a UE in an enhanced coverage mode over an extended period to accumulate energy at the receiving device or eNB respectively.
Furthermore, to reduce the cost and power consumption of various devices, the transmission bandwidth for MTC UEs may be reduced. Since transmissions using a large number of repetitions increase the device power consumption as well as decrease system-level resource utilization and spectral efficiency, additional techniques to improve the link budget like frequency hopping mechanisms may be used to reduce the number of repetitions for reduced bandwidth UEs and UEs in enhanced coverage mode.